Traditionally, many materials used in the production of nonwovens are prepared from thermoplastic polymers, such as polyester, polystyrene, polyethylene, and polypropylene. These polymers are generally very stable and can remain in the environment for a long time. Recently, however, there has been a trend to develop articles and products that are considered environmentally friendly and sustainable. As part of this trend, there has been a desire to produce ecologically friendly products comprised of increased sustainable content in order to reduce the content of petroleum based materials.
One promising polymer that may meet this desire is polylactic acid (PLA). Polylactic acid, also known as polylactide, is a renewable thermoplastic, aliphatic polyester derived from renewable resources, such as sugar, starch, or cellulose. PLA is promising because it is manufactured from natural substances, such as corn, and therefore may provide a sustainable alternative to petrochemical-derived products.
However, PLA does not necessarily have the same strength and elongation properties that may be associated with synthetic polymers, such as polyethylenes and polypropylenes. As a result, composite products have been developed that include a PLA component and a synthetic polymer component. One such product is a nonwoven sheet material comprising bicomponent filaments having a PLA core and a polypropylene sheath. Such products have found use in the diaper industry where it is a goal to increase the level of sustainable components in the consumer products.
However, the use of such composite material may also present disadvantages. One such disadvantage is due to the difficulty in reclaiming or recycling materials that are a composite of synthetic and sustainable polymers. As a result, the use of such materials has led to increased costs, which in turn, has limited the use of such materials in commercial products.
Accordingly, a need still exists for improved methods and products for incorporating sustainable polymers, such as PLA, into commercial products.